Finishes PENDING_STEPS Step 1 under the current trailing-exit model.
M15 window 2025-03-30->2026-05-31 ($0.30 spread): +116.6R/460 PF 1.83
vs +105.4R/424 PF 1.82 baseline, better in both halves; 2024-06->
2025-03 OOS +30.3R vs +10.6R control. Same knob on the pinned M5 book
is WORSE (+131.3R/699 vs +139.9R/547) so the override is M15-only in
the xauusd factory, per the pre-registered decision rule. M5 path
unchanged (factory override gated on primary_tf == M15).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Ported from feature/eurusd-support: PAIR_PRODUCERS registry with
make_config() factories per pair. xauusd.make_config is a pure
PlatformConfig-defaults wrapper (equality with the inline construction
is enforced by test); eurusd.make_config carries the donor branch's
regime weights and gates as a pre-realism baseline.
Adds 4 registry tests. 154/154 pass.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>